it is a lack of pigmentation. It is the only DQ in our breed being a dudley nose. The nose should be very black. I believe he also has no pigmentation around his eyes but is pink. It's something a reputable breeder would consider when breeding.

I noticed Molly started to get a lighter brown area on her nose. I googled it and turns out to be something called snow nose or winter nose. The pigmentation changes during colder months. Hers definitely isn't pink though and it is hardly noticeable to anyone other than me who knows exactly how she usually looks!